Starlin Castro homered in the fifth and played hero in the ninth, delivering a game-winning double as the Cubs avoided what would have been an ugly loss and defeated the Giants 4-3.

The Giants scored all three of their runs off new Cubs closer Kyuji Fujikawa in the ninth, taking Matt Cain off the hook and erasing a strong outing from Carlos Villanueva.

However, Sergio Romo, who was a perfect 6-for-6 in save chances this year, couldn’t hold the lead. He surrendered a rare homer to switch-hitter Dioner Navarro — just the fourth homer he’s ever allowed to a left-handed hitter — and then gave up two more hits, including Castro’s game-ender.

Some thoughts:

– Villanueva is the game’s unluckiest pitcher 12 days in. He left with a 5-1 lead over the Braves in his first start, only to see that blown. Today, his relievers needed to get just five outs, but still couldn’t hold a 2-0 lead. That’s left Villanueva 0-0 despite a 0.64 ERA.

– Castro could have ended the game 20 minutes earlier if he wanted. Hunter Pence hit what appeared to be a rally-killing double play ball Castro’s way in the top of the ninth, but Castro, even though he was as close to third as he was to second, went with an underhand toss to Alberto Gonzalez. The relay ended up being a bit slow, allowing Pence to barely beat it out.

– Castro also chose not to run on his game-ending double to the wall in center, thinking it was a homer. It didn’t matter a whole lot — the runner at first base was the one that mattered — but the game’s outcome would have still been in doubt had David DeJesus not come all of the way around to score.

– The homer hit by Navarro was an incredible oddity. Romo had allowed just three homers in 290 at-bats against left-handers previously, and the switch-hitting Navarro had homered off righties once every 65 at-bats, compared to once every 29 at-bats versus lefties.

– Before he became a closer, Romo was really more of a righty specialist in the San Francisco pen, often sharing innings with Jeremy Affeldt and Javier Lopez. His numbers against lefties were still terrific, but part of that is because he wasn’t typically getting to face the good ones. That’s changing now that the ninth inning is his alone, so it will be interesting to see if he proves more vulnerable to lefties.

Paxton, 30, has been among the game’s better starters over the past few years. In 2018, he went 11-6 with a 3.76 ERA and a 208/42 K/BB ratio in 160 1/3 innings. The lefty has two more years of arbitration eligibility remaining after earning $4.9 million this past season.

Sheffield, 22, is the headliner in the Mariners’ return. He made his major league debut in September for the Yankees, pitching 2 2/3 innings across three appearances. Two of those appearances were scoreless; in the third, he gave up a three-run home run to J.D. Martinez, certainly not an uncommon result among pitchers. MLB Pipeline rates Sheffield as the Yankees’ No. 1 prospect and No. 31 overall in baseball.

Thompson-Williams, 23, was selected by the Yankees in the fifth round of the 2016 draft. This past season, between Single-A Charleston and High-A Tampa, he hit .299/.363/.546 with 22 home runs, 74 RBI, 63 runs scored, and 20 stolen bases in 415 plate appearances. He was not among the Yankees’ top-30 prospects, per MLB Pipeline.

Swanson, 25, was selected by the Yankees in the eighth round of the 2014 draft. He spent most of his 2018 campaign between Double-A Trenton and Triple-A Scranton/Wilkes-Barre. Overall, he posted a 2.66 ERA with a 139/29 K/BB ratio in 121 2/3 innings. MLB Pipeline rated him No. 22 in the Yankees’ system.

This trade comes as no surprise as the Yankees clearly wanted to upgrade the starting rotation and the Mariners seemed motivated to trade Paxton this offseason. To the Mariners’ credit, they got a solid return for Paxton, as Sheffield likely becomes the organization’s No. 1 prospect. The only worries about this trade for the Yankees is how Paxton will fare in the more hitter-friendly confines of Yankee Stadium compared to the spacious Safeco Field, and Paxton’s durability. Paxton has made more than 20 starts in a season just twice in his career — the last two years (24 and 28). The Yankees are likely not done adding, however. Expect even more new faces before the start of spring training.